Anything to do with money, like a bank, should be doable in person (though I hope like hell she didn't get into those). If your credit card is in stuff like Amazon, you may want to cancel them.
First thing to try is generally your email account. From there, you can send password resets for most other accounts.
Try talking to the email provider - if you set up your account with a cellphone number, you might be able to get them reset.
Last option would be to go to a lawyer and see what they can do.